There are a lot of questions here in this thread that should be settled easily by listening. Most of these problems or issues are so room related, unique to each room, or speakers related, there is not size fits all answer.
Speakers have a designed dispersion pattern in the horizontal plane and vertical plane. The higher the frequency the more narrow the dispersion gets (in ALL speakers). Knowing that, using pink noise can help a great deal in hearing the differences in speaker dispersion as you move about. Pink noise makes it easy to notice changes in angle and position of the speakers relative to your position.
Get a pink noise disc and try it!
Brad